The choice of an ISO auditor is a critical decision that can reverberate through your organization, affecting not only your immediate compliance with ISO standards, but the overall efficacy and stability of your business operations. A rightful selection of an auditor can be a game-changer, one that propels your organization towards the zenith of quality and excellence.

However, selecting the right ISO auditor can be a daunting task, especially when your business is set against the backdrop of a rapidly evolving global regulatory environment and the increasing complexity of business operations. It requires a deep understanding of the ISO auditing process, the various ISO standards, and the nuances of your industry. Moreover, with the influx of auditors in the market, the choice can become even more perplexing.

So, how can you ensure that you are selecting the right ISO auditor? The answer lies in asking the right questions.

One of the first queries should concern the auditor's qualifications and experience. An auditor should have a minimum of a bachelor's degree in a field related to your industry, along with a certification from a recognized auditing body. Moreover, they should have several years' worth of experience in ISO auditing, and preferably in your industry.

Additionally, an in-depth understanding of various ISO standards is a sine qua non for an ISO auditor. As different ISO standards cater to different aspects of business operations, the auditor should be well-versed in the standard that is relevant for your business. Thus, asking about the auditor's familiarity with, and understanding of, the relevant ISO standard (like ISO 9001 for quality management, ISO 14001 for environmental management, etc.) is paramount.

Another critical aspect to consider is the auditor's approach to auditing. Does the auditor employ a compliance-based approach or a risk-based approach? The former focuses on meeting the minimum regulatory requirements, while the latter goes beyond, identifying potential risks and providing recommendations for mitigations. An auditor adopting a risk-based approach would arguably add more value to your business.

To ensure an effective auditing process, the auditor should have a comprehensive and systematic audit plan. This plan should detail the areas to be audited, the methodology, the timeline, and the resources required. Therefore, asking the auditor about their audit plan provides valuable insight into their auditing methodology.

The ISO auditor's communication skills also deserve scrutiny. Auditing is not just about identifying non-compliance and risks, it also involves effectively conveying the findings to the management and the workers. An auditor who can communicate clearly and convincingly can facilitate a better understanding within the organization, thus enabling more effective implementation of the recommendations.

Furthermore, the auditor's ongoing professional development is a crucial factor to consider. The world of ISO standards is continually evolving, and newer standards are being introduced regularly. Therefore, the auditor should be committed to ongoing learning and keeping themselves updated with the latest developments in the field.

Lastly, the auditor's fee is a significant consideration. While it shouldn't be the deciding factor, it's an important one nonetheless. The auditor's fee should be commensurate with their qualifications, experience, and the complexity of the audit.

In conclusion, choosing the right ISO auditor for your business is not a decision to be taken lightly. Rather, it requires an informed, deliberate approach, one that involves asking the right questions. Indeed, the questions you ask could very well determine the quality and efficacy of your ISO audit, and by extension, the robustness and resilience of your business operations.